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' P. L. POPE.

MULTIPLE LOCAL CIRCUIT FOR ELEGIRIO TELEGRAPHY. No. 329,411.

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UNITED STATES ATENT Fries.

FRANK L. POPE, OF ELIZABETH, NET/V JERSEY.

MULTIPLE LOCAL CIRCUIT FOR ELECTRIC TELEGRAPHY.

SPECIFICATION forming part of Letters Patent No. 329,411, dated October 27, 1885.

Application filed March 12, 1885. Serial No. 158,569. (No model.)

To all whom it may concern:

Be it known that I, FRANK L. POPE, a citizen of the United States, residingin Elizabeth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Multiple Local Circuits for Electric Telegraphy, of which the following is a specification.

In making use of the dynamo-electric machine for the purpose of supplying electric currents for large telegraph-stations the employment of such machines for the supply of the local circuits, which, as is well known, consu me by far the larger portion of the total electric energy required at any one station, has heretofore been attended with much practical difficulty. The volume or strength of electric current required in each local circuit is many times greater than that required in any of the .main or long line circuits, and each individual local circuitis, moreover, required to be alternately made and broken without appreciably affecting any of the others. These requirements have hitherto madeit necessary to group the local circuits in parallel or multiple ,arc with the generator. The resistance of the 10- cal circuits,inclu'ding the sounder-the instrument ordinarily used-is only about four ohms, and for this reason, when a very large number of the3efor example, one hundred, or more are placed in multiple are with a single dynamo-machine, the combined or joint resistance of all thelocal circuits becomes considerably less than the minimum resistance which itis practicable to give to the dynamo-electric ma chine; and hence under these circumstances the greater portion of the total electrical energy developed is expended in the useless and -1'njuri0us heating of the machine itself.

My invention consists in an improved organization of the local circuits of a large telegraph-station, by means of which each sounder may be independently supplied with its proper proportion of electrical energy, and may be actuated without appreciably affecting the operation of their instruments supplied from the same source, while at the same time any desired proportion between the resistance of the armature of the dynamo-electric machine and the total resistance offered by the work to be done may be established and maintained.

My invention also comprises means by which short or local telegraph lines, technically termed loops or branches, may be supplied from the same source with electric currents at any required potential.

The accompanying drawing is a diagram illustrating my invention.

In carrying out my invention I divide the whole number of local circuits, branch lines, loops, &c., into a certain number of groups, and I provide a dynamo-electric machine for supplying current to the whole system, which is capable of furnishing its terminals a potential equal to the highest potential required by any of the loops or branches connected therewith. I have shown,for example, in the drawing one branch or loop line, L, requiring for its proper operation a potential, say, of four volts, in the circuit of which is placed asounderor other telegraph receiving-instrument, s, and a circuit breaker or key, k, of well-known construction. I have also shown in the drawing twenty-four ordinary local sounders, each accompanied by its controlling relay or Circuit-breaker, the actuating electro-magnet of which is includedin a separate and independent main-line circuit. These local sounders, as ordinarily constructed, require a potential of about one volt, which is only one-quarter as much as the loop or branch line'hereinbefore referred to. In accordance with the principle of my invention, I have distributed these twenty-four sounders,with their corresponding 10- cal circuits and independently-actuated circuit-breakers, into four distinct groups having six soundersin each group. The first group, in which the individual sounders are marked S, are connected in parallel or multiple are between the conductors 0 O and l 1, the second group, S in like manner between conductors 1 l and 2 2, the third group, S between conductors 2 2 and 3 3, and the fourth group, S", between conductors 3 3 and 4 4.

The dynamo-electric machine, which serves as an electric generator for the entire system, is preferably of the typeknown as the shuntwound dynamo, in which the field-magnets f f and the armature A are connected in multiple are between the terminals as y of the machine, the field-circuit W being provided with an adjustable rheostat, R, by which the electro-motive force or potential of the machine may be varied,when required, in amanner well understood. The terminals my of the machine are connected by leads to and to with the conductors O O and 4 4.

It will be understood by reference to the drawing that the individual members of each group of sounders, local circuit, and circuitbreakers are arranged in multiple arc, while the groups themselves are placed in series he tweenthe leads proceeding from the terminals of the dynamo-electric generator. In consequence of this arrangement the difference of potential between the terminals of any one of the local circuit-s will varybut little fromone' volt,while the difference of potential between theterminals of the loop or branch wire in which the sounder s is included will be four volts. It is obvious that any other'branches or loops requiring a potential intermediate between one and four volts may have the terminals attached'to any two of the'cond-uctors between the groups of the series havingrequisite difference of potential.

In the ordin'aryoperation of a-telegraphic soundermaking use of theconventional alphaofa group of local circuits placedin multiple, arc in the manner shown in the drawing that at least half these circuits will be closed at'any given moment,'as each electro-magnet-is acting independently of the others in a separate main line and operating its own circuit-controller; hence a sufficient volume of current will at all times pass through the closed circuits of one-group to supply an equal number of closed circuits in the next group, and so on.

vide-as a safeguard a continuous or unbroken electrical connection between the terminals of each group, consisting of an adjustable rheostat, as shown at rWWr. By diminishing the resistance of either one of these rheostats a greater volume of current is permitted to flowthrough the adjacent groups. Each one of the branch or loop lines is also provided with arheostat, asshown at R, by which the volume of current flowing through the circuit of the branch or loop may be more accurately adjusted than could be conveniently done by varying the potential at one or both terminals. It is obvious that the best results In case, however, the flow of current through any one of the groups should at any time be found insufficient for the proper supply of one or more of the other groups of the series. I prowill be obtained when all the sounders and local circuits in the system present approximately the same electrical resistance. The total resistance presented by the entire system of local circuits and sounders will depend upon three thingsthe individual resistance of the sounders, 'the number of them placed in multiple arc in each group, and the number of groups placed in series. As each of these three elements may in practice be varied within wide limits, it is obvious that in accordance withthe principle of my invention persons skilled in the art may combine and arrange any number of local circuits from a few up to many thousand, and yet maintain the required-ratio between the resistance of the system'asa whole and thatof the armature of the dynamo-'machinea matter which is of the utmost importance inorder'toobtain the highest possible degree of economy and efficiency.

I claim as my invention- 1. The combination of an electric generator, two or more-groups of sounders'or'other local receiving-instruments deriving theiractuau' ently actuated by electro-maguets placed in different main-lineci'rcuits.

2. The combination of an electric generator, two or more groups of sounders or other local receiving-instruments deriving their actuating current therefrom, 'such groups being placed inseries, while the individual'sounders or receiving-instruments composing each group are placed in parallel branches, an independent circuitcontroller in'each of said parallelbranches, and an adjustable 'rheostati-n an additional parallel branch of each group.

3. The-combination of an electric generator,

two or more groups of sounders or other receiving-instruments deriving their actuatingcurrent therefrom, said groups being placed in series, while the individual sounders or receiving-instruments of each group are placed in parallel branches, and one or more additional branches or circuits containing apparatus for transmitting or receiving telegraphic signals, placed parallel to two or more of said groups, and deriving their current from the same source.

In testimony whereof I have hereunto subscribed my name this 26th day of February, A. D. 1885.

. FRANK L. POPE.

Witnesses: V

DANL. W. EDGEGOMB, OHARLEsA. TERRY. 

